The effect of Poly-ethylene-co-glycidyl methacrylate efficiency and clay platelets on thermal and rheological properties of wood polyethylene composites.

Global ecological concerns have resulted in an interest in renewable natural materials. Composites based on high density polyethylene (HDPE), wood fiber (Veneer) and containing coupling agents like nanoclay (NC) and poly-ethylene-co-glycidyl methacrylate (PEGMA) were made by melt compounding and then injection molding. In this study, the effects of two variable parameters namely nanoclay and coupling agent on the rheological and thermal properties of wood polyethylene composites (WPECs) were investigated. The study investigates the morphology phase, rheology behaviors and thermal properties by scanning electron microscope, capillary rheometer and thermal gravimetric analyzer. The SEM micrographs of the composites showed that the outer surfaces of the wood were coated by a section of amorphous lignin. The state of dispersion in HDPE/pine/clay composites was improved by EGMA because it could interact with pine flour in addition to clay. The interaction of reinforcement with coupling agent and HDPE matrix is strong based on the observation of the fracture surface of composites when EGMA is present. However the addition of 2.5% clay slightly lowered the initial degradation temperature (Td) but did not improve the thermal stability. Obviously, all the composites materials exhibit viscoelastic values greater than those of neat HDPE.

Analytical Modeling and Determination of the Characteristic Parameters of the Different Commercial Technologies of Photovoltaic Modules

This work presents a method of optimization of the photovoltaic generator (PV) based on the electrical model with a diode. The method consists of solving a second degree equation representing the derivative of the power function. The current and the maximum voltage being determined, the maximum power is deduced. Four popular types of photovoltaic panels from different manufacturers were considered for the study: BYD Model (BYD 320P6C-36), Atersa Grupo Model (A-320P GSE), SunPower Model (E19-320) and Model operated in the 50 MW power plant of Nouakchott-Mauritania (JKM320PP-72-V) of JinkoSolar. A comparative study is carried out between the simulated results and the data of the manufacturer of different technologies. The results obtained prove the effectiveness of the proposed method and that the BYD 320P6C-36 model is the most efficient among the four different technologies studied.

Homer’s Feasibility Analysis of a Hybrid System with a Grid Connection Option for the Mauritanian Northern Coast

On Mauritania’s northern coast, wind and solar resources are abundant and must be used effectively. These resources have the potential to completely or partially replace the existing or projected diesel generators. The main objective of this case study is to study the possibility of using a hybrid system (HS) of the type (diesel, wind and storage). The most important part of this case study intended for this area will be to add the solar in a first phase and then the incorporation of an interconnection with the nearby network in a second phase. This interconnection will be secured by mean of medium voltage lines of 33 kV, where the nearest point is located 35 km away. Indeed, the study of the optimization model is carried out through Homer, which was developed by National Renewable Energy Laboratory [NREL]. Thus, it should be noted that the HS is analyzed on the basis of costs ($/kW) and price ($/kWh) and greenhouse gas emissions. Therefore, in order to achieve these techno-economic optimization objectives, this paper introduces a sensitivity analysis that has been proposed to determine the effect of costs on each HS configuration. In the end, HSs are needed for maximum use of renewable resources at the studied site for an uninterrupted power supply.

Evaluation of Sawdust and Rice Husks as Fillers for Phenolic Resin Based Wood-Polymer Composites

We produced Wood-Polymer Composites (WPCs) with phenolic resin (PR) filled with saw dust (SD) and rice husks (RH) in a PR:fillerratio of 60:40 wt.%. RH and SD were grinded and sieved into particles μm. The aim of this research work was to evaluate sawdust and rice husks as fillers for sustainable phenolic resin based WPCs. Therefore, we investigated the thermal stability of PR/RH and PR/SD WPCs then we studied and compared the tensile, flexural properties of PR/SD and PR/RH WPCs samples, as well as their dimensional stability after water absorption test. Furthermore, through ultraviolet light exposure, we evaluated the effects of photo-oxidation on the water stability and mechanical properties of PR/RH and PR/SD WPCs samples compared to unexposed ones. PR filled with SD presented better mechanical properties compared to PR/RH WPCs samples. However, PR/RH WPCs showed good mechanical properties, and better thermal resistance and better water repulsion capabilities compared to PR/SD WPCs samples. Although, long time UV exposure ended up lowering considerably the mechanical properties and water resistance of PR/SD and PR/RH WPCs, both RH and SD offer great added value as fillers for PR based WPCs;SD having better interactions with PR matrix compared to RH.

Influence of Temperature and Pentacene Thickness on the Electrical Parameters in Top Gate Organic Thin Film Transistor

In this contribution, we report on the effect of pentacene thickness and temperature on the performance of top gate transistors. We first investigated the temperature dependence of the transport properties in the temperature range of 258 K - 353 K. The electrical characteristics showed that the threshold voltage (VT) and the onset voltage (Von) remain unchanged. However, the subthreshold current (Ioff), the on-current (Ion) and the field effect mobility (μ) are highly affected with a slight deterioration of subthreshold slope. We observed Arrhenius-like behavior suggesting a thermally activated mobility with an activation energy EA = 68 meV. Moreover the dependence of the charge carrier mobility on the organic semiconductor thickness has also been studied. The mobility decreased as the pentacene thickness increases whereas the threshold voltage and Ioff current remain minimally affected. In order to understand the transport properties and in view to put in light morphology peculiarities of pentacene, AFM images were performed. It turns out that the pentacene grain sizes are smaller and disorganized as the film thickness increases, and charge carriers are more prone to be trapped, leading to decrease the field effect mobility and the Ion current. The devices were also tested under bias stress and the transistors with low thicknesses exhibited a relatively good electrical stability compared to those with high pentacene thicknesses. This work points out the influence of temperature, semiconductor thickness and bias stress effect on the device performance and stability of transistor using top gate configuration.